Comment by Gibbon1

Commonly these components were modular just based on some of the ones I've handled decades ago.

Imagine a configurable rotary switch.

You have the knob part available in a selection of styles and colors.

You have the switch body, which can come in different types, single pole, two pole, NC, NO ext. One I saw you could stack them.

Then you had a basemount with terminal connections, screw, solder, etc.

I've handled decade encoders, stackable numbered encoders. The more convenient ones the the computer could read the selected numbers like you do keyboard matrix.

Peek 1960-70s industrial design. Still available.

https://www.digikey.com/en/products/category/configurable-sw...